The organizational state of the double-stranded (ds) RNA in the yeast LA virus capsid is being investigated by cryo-electron microscopy. In most other viruses, ds DNA or RNA is packed with a characteristic inter-duplex spacing of 26 . In LA virus, this figure is 35-40 suggesting that the fibrillar unit to which it corresponds is larger than a single duplex. STEM measurements of mass/length are being performed on RNA released from disrupted LA capsids compared to purified dsRNA to test this hypothesis.